1. Field of the Invention
This invention relates to polyfunctional aziridines for use in crosslinking applications which are the reaction products of ethylene iminie and acrylates of alkoxylated trimethyol propane, neopentyl glycol, pentaerythritol, bis phenol A, bis phenol F and glycerol.
2. Description of the Prior Art
Polyfunctional aziridines have been shown to be useful as crosslinking agents in various types of coating systems such as carboxylated acrylics, vinyl-acetate, carboxylated urethanes and styrene acrylics. Commercially available polyfunctional aziridines are trifunctional in character and are reaction products of ethylene imine or propylene imine with trimethylol propane triacrylate and ethylene imine with pentaerythritol triacrylate. They are effective low temperature crosslinking agents when added to a coat system in amounts of 0.2 to 5.0% by weight of total formula.
The choice of crosslinking agent used in a coating system has a significant effect on the preparation of the coating system as well as on the overall properties of the cured coating. Factors such as water solvency, viscosity, and functionality will have a bearing on the ease of preparing the coating.
Regarding the previously mentioned polyfunctional aziridines which are used commercially, these materials are effective crosslinking agents but tend to be low in water solubility, have negative features in toxicity and are poor in corrosion, adhesion and humidity resistance.
The above and other polyfunctional aziridines are, for example, described in the following patents:
______________________________________ 2,596,200 Bestian May 13, 1952 3,165,375 Tesoro January 12, 1965 3,197,463 Tesoro et al July 27, 1965 3,285,798 Tesoro November 15, 1966 3,338,885 Coker et al August 29, 1967 3,597,146 Tesoro August 3, 1971 3,726,862 Coker et al April 10, 1973 ______________________________________
Aqueous coating composition containing aziridine crosslinking agents are described in U.S. Pat. No. 4,278,578--Carpenter, July 14, 1981.